Dual-pressure flash evaporation waste heat power generation device

Abstract

The dual-pressure flash evaporation waste heat power generation device comprises a dual-pressure waste heat boiler, a steam turbine, a power generator, a coupling flash evaporation tank and a water supply system, the steam turbine comprises a high-pressure section and a low-pressure section, and the dual-pressure waste heat boiler comprises a high-pressure section and a low-pressure reheating section; a steam outlet of a high-pressure section of the dual-pressure waste heat boiler is connected with an inlet of a high-pressure section of the steam turbine, an outlet of the high-pressure section of the steam turbine is connected with a steam inlet of the coupling flash tank, a saturated water outlet of the dual-pressure waste heat boiler is connected with a saturated water inlet of the coupling flash tank, and a saturated water outlet of the coupling flash tank is connected with an inlet of the water supply system. The water supply system supplies water to the high-pressure section of the dual-pressure waste heat boiler; a steam outlet of the coupling flash tank is connected with a steam inlet of a low-pressure reheating section of the dual-pressure waste heat boiler, a steam outlet of the low-pressure reheating section of the dual-pressure waste heat boiler is connected with an inlet of a low-pressure section of the steam turbine, and a condenser is arranged at an outlet of the low-pressure section of the steam turbine. The humidity of the last-stage blade of the steam turbine can be reduced, and the service life is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat utilization, and in particular to a dual-pressure flash evaporation waste heat power generation device. Background Art

[0002] In the technology of utilizing waste heat from industrial flue gas, single-pressure waste heat power generation technology, flash waste heat power generation technology and dual-pressure waste heat power generation technology are widely used. Among them, due to the limitation of single pressure, the exhaust temperature of the waste heat boiler is too high, the waste heat resources in the flue gas cannot be fully utilized, or the steam parameters are low, which makes it difficult to improve the power generation efficiency; the flash waste heat power generation technology uses high-pressure hot water to pass through the reduced-pressure flash tank to obtain low-pressure saturated steam, which is fed into the steam turbine for power generation. The amount of supplementary steam has good adjustability, but a large amount of saturated steam is fed into the steam turbine, resulting in a decrease in exhaust steam dryness and a reduction in the life of the last-stage blades; in the dual-pressure waste heat power generation technology, the boiler exhaust temperature is limited by the evaporation amount, and the boiler exhaust temperature cannot be reduced to the maximum extent. It does not have a good boiler exhaust temperature regulation ability, and the low-pressure steam supplementary steam amount is also limited by the steam turbine, so the power generation is affected to a certain extent. In today's energy-scarce world, the heat in the flue gas waste heat should be recovered and utilized more efficiently and flexibly.

[0003] To this end, the present application proposes a dual-pressure flash waste heat power generation device. Summary of the invention

[0004] In view of the problem of short life of turbine blades in the above-mentioned existing waste heat power generation technology, the present invention proposes a dual-pressure flash waste heat power generation device, and the specific technical solution is as follows: A dual-pressure flash waste heat power generation device comprises a dual-pressure waste heat boiler, a steam turbine, a generator, a coupled flash tank, a water supply system, a condenser, a condensate pump and a steam seal heater, the steam turbine comprises a high-pressure section and a low-pressure section, the dual-pressure waste heat boiler comprises a high-pressure section and a low-pressure reheat section; the steam outlet of the high-pressure section of the dual-pressure waste heat boiler is connected to the inlet of the high-pressure section of the steam turbine, the outlet of the high-pressure section of the steam turbine is connected to the steam inlet of the coupled flash tank, the saturated water outlet of the dual-pressure waste heat boiler is connected to the saturated water inlet of the coupled flash tank, and the saturated water outlet of the coupled flash tank is connected to the water supply system the steam outlet of the coupling flash tank is connected to the steam inlet of the low-pressure reheat section of the double-pressure waste heat boiler, the steam outlet of the low-pressure reheat section of the double-pressure waste heat boiler is connected to the inlet of the low-pressure section of the steam turbine, the outlet of the low-pressure section of the steam turbine is connected to the inlet of the condenser, the outlet of the condenser is connected to the inlet of the condensate pump, the inlet of the condensate pump is connected to the inlet of the steam seal heater, the outlet of the steam seal heater is connected to the inlet of the feed water system, and the outlet of the feed water system is connected to the feed water inlet of the high-pressure section of the double-pressure waste heat boiler; the steam turbine and the generator are connected to form a steam turbine power generation system.

[0005] Furthermore, a first bypass for high-pressure steam to pass through is provided between the high-pressure section of the dual-pressure waste heat boiler and the steam inlet of the coupled flash tank, and a switch valve is provided on the first bypass.

[0006] Furthermore, a second bypass for low-pressure steam to pass through is provided between the low-pressure reheat section of the dual-pressure waste heat boiler and the inlet of the condenser, and a switch valve is provided on the second bypass.

[0007] Furthermore, the double-pressure waste heat boiler uses chemical deoxidation, thermal deoxidation, vacuum deoxidation or condenser vacuuming to deoxidize.

[0008] Furthermore, it also includes a circulating water pump and a cooling tower, and the heat exchange pipeline in the condenser is connected to the cooling tower through the circulating water pump.

[0009] Furthermore, the saturated water outlet of the dual-pressure waste heat boiler is located on the high-pressure section; the water supply system includes a high-pressure water supply pump, and the outlet of the high-pressure water supply pump is connected to the water supply inlet of the high-pressure section of the dual-pressure waste heat boiler.

[0010] Furthermore, the dual-pressure waste heat boiler also includes a low-pressure section, and the steam outlet of the low-pressure section of the dual-pressure waste heat boiler is connected to the steam inlet of the coupled flash tank; the water supply system also includes a low-pressure feed water pump, and the outlet of the low-pressure feed water pump is connected to the feed water inlet of the low-pressure section of the dual-pressure waste heat boiler.

[0011] Furthermore, the steam volume of the low-pressure section of the double-pressure waste heat boiler and the steam volume of the high-pressure section of the double-pressure waste heat boiler are decoupled from the flue gas intake volume and the boiler exhaust temperature.

[0012] Optionally, the saturated water outlet of the dual-pressure waste heat boiler is located on the low-pressure section.

[0013] The beneficial effects of the present invention are: By inputting high-pressure saturated water and steam that has done work in the high-pressure section of the steam turbine into the coupled flash tank, low-pressure saturated water and low-pressure steam are generated. After the low-pressure steam enters the low-pressure reheating section of the boiler for reheating, the low-pressure reheated steam enters the low-pressure section of the steam turbine to do work. The present invention increases the steam inlet temperature of the low-pressure section of the steam turbine by reheating the low-pressure steam, thereby reducing the humidity of the last stage of the steam turbine, which can greatly improve the operating safety of the steam turbine and extend the life of the unit; at the same time, the amount of saturated water entering the double-pressure waste heat boiler can be adjusted to achieve flexible adjustment of the exhaust gas temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0015] Figure 1 is a schematic diagram of a dual-pressure flash waste heat power generation device in Embodiment 1 of the present invention; Figure 2 is a schematic diagram of a dual-pressure flash waste heat power generation device in Embodiment 2 of the present invention; Figure 3 It is a schematic diagram of the dual-pressure flash waste heat power generation device in Example 3 of the present invention.

[0016] In the figure: 1. high-pressure section of double-pressure waste heat boiler; 2. high-pressure drum; 3. high-pressure section of steam turbine; 4. generator; 5. coupled flash tank; 6. high-pressure feed water pump; 7. low-pressure reheat section of double-pressure waste heat boiler; 8. low-pressure section of steam turbine; 9. condenser; 10. condensate pump; 11. steam seal heater; 12. first bypass; 13. second bypass; 14. low-pressure feed water pump; 15. vacuum deaerator; 16. low-pressure drum; 17. thermal deaerator; 18. low-pressure section of double-pressure waste heat boiler; 19. cooling tower; 20. circulating water pump. DETAILED DESCRIPTION

[0017] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0018] Embodiment 1: like Figure 1As shown, taking an inverted vertical double-pressure waste heat boiler as an example (flue gas enters from the bottom and exits from the top), the boiler inlet and the settling chamber are integrated into a design that is beneficial to flue gas ash removal. The present invention provides a double-pressure flash waste heat power generation device, comprising a double-pressure waste heat boiler, a steam turbine, a generator 4, a coupled flash tank 5, a water supply system, a condenser 9, a condensate pump 10 and a steam seal heater 11. The steam turbine comprises a steam turbine high-pressure section 3 and a steam turbine low-pressure section 8. The double-pressure waste heat boiler comprises a double-pressure waste heat boiler high-pressure section 1 and a double-pressure waste heat boiler low-pressure reheat section 7. The steam outlet of the double-pressure waste heat boiler high-pressure section 1 and the inlet of the steam turbine high-pressure section 3 are connected by a pipeline, the outlet of the steam turbine high-pressure section 3 and the steam inlet of the coupled flash tank 5 are connected by a pipeline, the saturated water outlet of the double-pressure waste heat boiler and the saturated water inlet of the coupled flash tank 5 are connected by a pipeline, and the saturated water outlet of the coupled flash tank 5 and the water supply system The inlets of the systems are connected by pipelines; the steam outlet of the coupling flash tank 5 is connected to the steam inlet of the low-pressure reheat section 7 of the double-pressure waste heat boiler through a pipeline, the steam outlet of the low-pressure reheat section 7 of the double-pressure waste heat boiler is connected to the inlet of the low-pressure section 8 of the steam turbine through a pipeline, the outlet of the low-pressure section 8 of the steam turbine is connected to the inlet of the condenser 9 through a pipeline, the outlet of the condenser 9 is connected to the inlet of the condensate pump 10 through a pipeline, the inlet of the condensate pump 10 is connected to the inlet of the steam seal heater 11 through a pipeline, the outlet of the steam seal heater 11 is connected to the inlet of the water supply system through a pipeline, and the outlet of the water supply system is connected to the water supply inlet of the high-pressure section 1 of the double-pressure waste heat boiler through a pipeline; the steam turbine is connected to the generator 4 to form a steam turbine power generation system.

[0019] Furthermore, the saturated water outlet of the dual-pressure waste heat boiler is located on the high-pressure section 1 of the dual-pressure waste heat boiler, and the saturated water outlet of the high-pressure section 1 of the dual-pressure waste heat boiler is connected to the saturated water inlet of the coupled flash tank 5 through a pipeline; the water supply system includes a high-pressure feed water pump 6, and the outlet of the high-pressure feed water pump 6 is connected to the feed water inlet of the high-pressure section 1 of the dual-pressure waste heat boiler through a pipeline, and the saturated water outlet of the coupled flash tank 5 and the outlet of the steam seal heater 11 are merged and connected to the inlet of the high-pressure feed water pump 6 through a pipeline.

[0020] Furthermore, a first bypass 12 for high-pressure steam to pass through is provided between the high-pressure section 1 of the dual-pressure waste heat boiler and the steam inlet of the coupled flash tank 5. The high-pressure steam can pass through the first bypass 12 without entering the high-pressure section 3 of the steam turbine. A switch valve is provided on the first bypass 12 to control the on and off of the first bypass 12.

[0021] Furthermore, a second bypass 13 for low-pressure steam to pass through is provided between the low-pressure reheat section 7 of the dual-pressure waste heat boiler and the inlet of the condenser 9. The low-pressure steam can pass through the second bypass 13 without entering the low-pressure section 8 of the turbine. A switch valve is provided on the second bypass 13 to control the on and off of the second bypass 13.

[0022] Furthermore, the double-pressure waste heat boiler can be deoxidized by chemical deoxidation, thermal deoxidation, vacuum deoxidation or condenser vacuum extraction.

[0023] Furthermore, a liquid level gauge and a water replenishing device are provided on the coupled flash tank 5, so that the coupled flash tank 5 maintains a certain liquid level to prevent it from being sucked empty by the hot water pump.

[0024] Furthermore, it also includes a circulating water pump 20 and a cooling tower 19 , and the heat exchange pipeline in the condenser 9 is connected to the cooling tower 19 through the circulating water pump 20 .

[0025] Furthermore, the steam volume of the high-pressure section 1 of the dual-pressure waste heat boiler is decoupled from the flue gas intake volume and the boiler exhaust temperature. The high-pressure feed water pump 6 is of industrial frequency or variable frequency, and the feed water flow rate is adjusted by adjusting the valve. The control system controls the flow rate of the high-pressure feed water pump 6 through the flue gas intake volume and the set boiler exhaust temperature, and then controls the high-pressure steam volume generated by the high-pressure section 1 of the dual-pressure waste heat boiler.

[0026] In this embodiment, the high-pressure section 1 of the double-pressure waste heat boiler includes a high-pressure economizer, a high-pressure evaporator, a high-pressure drum 2 and a high-pressure superheater, and the low-pressure reheat section 7 of the double-pressure waste heat boiler includes a low-pressure reheater. During operation, high-temperature flue gas enters from the bottom air inlet of the double-pressure waste heat boiler, passes through the heating surfaces of the low-pressure reheat section 7 of the double-pressure waste heat boiler and the high-pressure section 1 of the double-pressure waste heat boiler in sequence, and is discharged from the upper air outlet of the double-pressure waste heat boiler and enters the exhaust system. The feed water from the high-pressure feed water pump 6 first enters the high-pressure economizer to produce high-pressure saturated water. A part of the high-pressure saturated water enters the high-pressure evaporator, the high-pressure drum 2, and the high-pressure superheater in turn to produce high-pressure steam. The high-pressure steam enters the high-pressure section 3 of the steam turbine to do work and is discharged into the coupled flash tank 5; the other part of the high-pressure saturated water enters the coupled flash tank 5 to merge with the exhaust steam from the high-pressure section 3 of the steam turbine, and produces low-pressure steam and low-pressure saturated water in the coupled flash tank 5; the low-pressure steam enters the low-pressure reheat section 7 of the double-pressure waste heat boiler for reheating to produce low-pressure reheat steam, and the low-pressure reheat steam enters the low-pressure section 8 of the steam turbine to do work. The exhaust steam of the low-pressure section 8 of the steam turbine is condensed into condensate through the condenser 9; the condensate passes through the steam seal heater 11 and merges with the low-pressure saturated water produced by the coupled flash tank 5, and then the merged water is pressurized again by the high-pressure feed water pump 6 and transported to the high-pressure economizer.

[0027] In this embodiment, high-pressure saturated water and steam that has done work in the high-pressure section 3 of the steam turbine are input into the coupled flash tank 5 to generate low-pressure saturated water and low-pressure steam. The low-pressure steam then enters the low-pressure reheat section of the boiler for reheating, and then enters the low-pressure section 8 of the steam turbine for work. By reheating the low-pressure steam, the steam inlet temperature of the low-pressure section 8 of the steam turbine is increased, thereby increasing the humidity of the last stage of the steam turbine. By adjusting the flow rate of high-pressure saturated water, the exhaust temperature of the boiler can be adjusted.

[0028] The problem of high humidity in the last-stage blades of the flash waste heat power generation steam turbine has been solved, which can greatly improve the operating safety of the steam turbine and extend the life of the unit. The problem that the boiler exhaust temperature cannot be flexibly adjusted due to the narrow temperature difference between steam and flue gas in the reheat power generation technology has been solved, so that the system thermal efficiency is always maintained at a high level and the operating flexibility is enhanced. The problem that the main steam pressure level is limited by the boiler exhaust temperature in the dual-pressure waste heat power generation technology has been solved, which can greatly improve the main steam pressure level and significantly improve the efficiency of the steam turbine.

[0029] Embodiment 2: like Figure 2 As shown, taking a vertically arranged double-pressure waste heat boiler (flue gas enters from top and exits from bottom) as an example, the present invention proposes a double-pressure flash waste heat power generation device, comprising a double-pressure waste heat boiler, a steam turbine, a generator 4, a coupled flash tank 5, a water supply system, a condenser 9, a condensate pump 10 and a steam seal heater 11, the steam turbine comprises a steam turbine high-pressure section 3 and a steam turbine low-pressure section 8, the double-pressure waste heat boiler comprises a double-pressure waste heat boiler high-pressure section 1, a double-pressure waste heat boiler low-pressure section 18 and a double-pressure waste heat boiler low-pressure reheat section 7; the steam outlet of the double-pressure waste heat boiler high-pressure section 1 and the inlet of the steam turbine high-pressure section 3 are connected by a pipeline, the outlet of the steam turbine high-pressure section 3 and the steam inlet of the coupled flash tank 5 are connected by a pipeline, the saturated water outlet of the double-pressure waste heat boiler and the saturated water inlet of the coupled flash tank 5 are connected by a pipeline, and the saturated water outlet of the coupled flash tank 5 and the inlet of the water supply system are connected by a pipeline. Pipeline connection; the steam outlet of the low-pressure section 18 of the double-pressure waste heat boiler is connected to the steam inlet of the coupled flash tank 5 through a pipeline, the steam outlet of the coupled flash tank 5 is connected to the steam inlet of the low-pressure reheat section 7 of the double-pressure waste heat boiler through a pipeline, the steam outlet of the low-pressure reheat section 7 of the double-pressure waste heat boiler is connected to the inlet of the low-pressure section 8 of the steam turbine through a pipeline, the outlet of the low-pressure section 8 of the steam turbine is connected to the inlet of the condenser 9 through a pipeline, the outlet of the condenser 9 is connected to the inlet of the condensate pump 10 through a pipeline, the inlet of the condensate pump 10 is connected to the inlet of the steam seal heater 11 through a pipeline, the outlet of the steam seal heater 11 is connected to the inlet of the water supply system through a pipeline, and the outlet of the water supply system is connected to the water supply inlet of the high-pressure section 1 of the double-pressure waste heat boiler and the water supply inlet of the low-pressure section 18 of the double-pressure waste heat boiler through pipelines respectively; the steam turbine is connected to the generator 4 to form a steam turbine power generation system.

[0030] Furthermore, the saturated water outlet of the dual-pressure waste heat boiler is located on the high-pressure section 1 of the dual-pressure waste heat boiler, and the saturated water outlet of the high-pressure section 1 of the dual-pressure waste heat boiler is connected to the saturated water inlet of the coupled flash tank 5 through a pipeline; the water supply system includes a high-pressure feed water pump 6 and a low-pressure feed water pump 14, the outlet of the high-pressure feed water pump 6 is connected to the feed water inlet of the high-pressure section 1 of the dual-pressure waste heat boiler through a pipeline, the outlet of the low-pressure feed water pump 14 is connected to the feed water inlet of the low-pressure section 18 of the dual-pressure waste heat boiler through a pipeline, and the combined outlet after the saturated water outlet of the coupled flash tank 5 and the outlet of the steam seal heater 11 are combined is respectively connected to the inlet of the high-pressure feed water pump 6 and the inlet of the low-pressure feed water pump 14 through a pipeline.

[0031] Furthermore, a first bypass 12 for high-pressure steam to pass through is provided between the high-pressure section 1 of the dual-pressure waste heat boiler and the steam inlet of the coupled flash tank 5. The high-pressure steam can pass through the first bypass 12 without entering the high-pressure section 3 of the steam turbine. A switch valve is provided on the first bypass 12 to control the on and off of the first bypass 12.

[0032] Furthermore, a second bypass 13 for low-pressure steam to pass through is provided between the low-pressure reheat section 7 of the dual-pressure waste heat boiler and the inlet of the condenser 9. The low-pressure steam can pass through the second bypass 13 without entering the low-pressure section 8 of the turbine. A switch valve is provided on the second bypass 13 to control the on and off of the second bypass 13.

[0033] Furthermore, in this embodiment, the double-pressure waste heat boiler uses a vacuum deaerator 15 for deoxygenation, and the vacuum deaerator 15 is arranged at the confluent outlet after the saturated water outlet of the coupled flash tank 5 and the outlet of the steam seal heater 11 are confluent.

[0034] Furthermore, a liquid level gauge and a water replenishing device are provided on the coupled flash tank 5, so that the coupled flash tank 5 maintains a certain liquid level to prevent it from being sucked empty by the hot water pump.

[0035] Furthermore, it also includes a circulating water pump 20 and a cooling tower 19 , and the heat exchange pipeline in the condenser 9 is connected to the cooling tower 19 through the circulating water pump 20 .

[0036] Furthermore, the steam volume of the high-pressure section 1 of the dual-pressure waste heat boiler and the steam volume of the low-pressure section 18 of the dual-pressure waste heat boiler are decoupled from the flue gas intake volume and the boiler exhaust temperature. The high-pressure feed water pump 6 is of industrial frequency or variable frequency, and the low-pressure feed water pump 14 is of industrial frequency or variable frequency. The feed water flow rate is adjusted by adjusting the valve. The control system controls the flow rates of the high-pressure feed water pump 6 and the low-pressure feed water pump 14 through the flue gas intake volume and the set boiler exhaust temperature, and then controls the steam volume of the high-pressure section 1 of the dual-pressure waste heat boiler and the steam volume of the low-pressure section 18 of the dual-pressure waste heat boiler.

[0037] In this embodiment, the high-pressure section 1 of the double-pressure waste heat boiler includes a high-pressure economizer, a high-pressure evaporator, a high-pressure drum 2 and a high-pressure superheater, the low-pressure reheat section 7 of the double-pressure waste heat boiler includes a low-pressure reheater, and the low-pressure section 18 of the double-pressure waste heat boiler includes a low-pressure economizer, a low-pressure evaporator, a low-pressure drum 16 and a low-pressure superheater. During operation, high-temperature flue gas enters from the top air inlet of the double-pressure waste heat boiler, passes through the heating surfaces of the high-pressure section 1 of the double-pressure waste heat boiler, the low-pressure reheat section 7 of the double-pressure waste heat boiler, and the low-pressure section 18 of the double-pressure waste heat boiler in sequence, and is discharged from the bottom air outlet of the double-pressure waste heat boiler and enters the smoke exhaust system. The feed water from the high-pressure feed water pump 6 enters the high-pressure economizer to produce high-pressure saturated water. A part of the high-pressure saturated water enters the high-pressure evaporator, the high-pressure drum 2, and the high-pressure superheater in turn to produce high-pressure steam. The high-pressure steam enters the high-pressure section 3 of the steam turbine to do work and is then discharged into the coupled flash tank 5; the feed water from the low-pressure feed water pump 14 enters the low-pressure economizer to produce low-pressure saturated water I, and the low-pressure saturated water I enters the low-pressure evaporator, the low-pressure drum 16, and the low-pressure superheater in turn to produce low-pressure steam I; in the coupled flash tank 5, another part of the high-pressure saturated water and the low-pressure steam I are mixed with the discharge water from the high-pressure section 3 of the steam turbine. The steam is combined and low-pressure steam II and low-pressure saturated water II are generated in the coupled flash tank 5; the low-pressure steam II enters the low-pressure reheat section 7 of the double-pressure waste heat boiler for reheating to generate low-pressure reheat steam, and the low-pressure reheat steam enters the low-pressure section 8 of the steam turbine to perform work, and the exhaust steam of the low-pressure section 8 of the steam turbine is condensed into condensed water through the condenser 9; the condensed water passes through the steam seal heater 11 and is combined with the low-pressure saturated water II generated by the coupled flash tank 5, and then the combined water passes through the vacuum deaerator 15, and the water feed system again transports the water to the high-pressure section 1 of the double-pressure waste heat boiler and the low-pressure section 18 of the double-pressure waste heat boiler.

[0038] This embodiment adds a low-pressure section 18 of a dual-pressure waste heat boiler, which can reasonably utilize the heat in the waste heat flue gas in a stepped manner, reduce the amount of low-pressure saturated water generated by the coupled flash tank 5, and reduce the risk of cavitation of the high- and low-pressure feed water pumps 14.

[0039] Embodiment three: like Figure 3As shown, taking a vertically arranged double-pressure waste heat boiler (flue gas enters from top and exits from bottom) as an example, the present invention proposes a double-pressure flash waste heat power generation device, comprising a double-pressure waste heat boiler, a steam turbine, a generator 4, a coupled flash tank 5, a water supply system, a condenser 9, a condensate pump 10 and a steam seal heater 11, the steam turbine comprises a steam turbine high-pressure section 3 and a steam turbine low-pressure section 8, the double-pressure waste heat boiler comprises a double-pressure waste heat boiler high-pressure section 1, a double-pressure waste heat boiler low-pressure section 18 and a double-pressure waste heat boiler low-pressure reheat section 7; the steam outlet of the double-pressure waste heat boiler high-pressure section 1 and the inlet of the steam turbine high-pressure section 3 are connected by a pipeline, the outlet of the steam turbine high-pressure section 3 and the steam inlet of the coupled flash tank 5 are connected by a pipeline, the saturated water outlet of the double-pressure waste heat boiler and the saturated water inlet of the coupled flash tank 5 are connected by a pipeline, and the saturated water outlet of the coupled flash tank 5 and the inlet of the water supply system are connected by a pipeline. Pipeline connection; the steam outlet of the low-pressure section 18 of the double-pressure waste heat boiler is connected to the steam inlet of the coupled flash tank 5 through a pipeline, the steam outlet of the coupled flash tank 5 is connected to the steam inlet of the low-pressure reheat section 7 of the double-pressure waste heat boiler through a pipeline, the steam outlet of the low-pressure reheat section 7 of the double-pressure waste heat boiler is connected to the inlet of the low-pressure section 8 of the steam turbine through a pipeline, the outlet of the low-pressure section 8 of the steam turbine is connected to the inlet of the condenser 9 through a pipeline, the outlet of the condenser 9 is connected to the inlet of the condensate pump 10 through a pipeline, the inlet of the condensate pump 10 is connected to the inlet of the steam seal heater 11 through a pipeline, the outlet of the steam seal heater 11 is connected to the inlet of the water supply system through a pipeline, and the outlet of the water supply system is connected to the water supply inlet of the high-pressure section 1 of the double-pressure waste heat boiler and the water supply inlet of the low-pressure section 18 of the double-pressure waste heat boiler through pipelines respectively; the steam turbine is connected to the generator 4 to form a steam turbine power generation system.

[0040] Furthermore, the saturated water outlet of the dual-pressure waste heat boiler is located on the low-pressure section 18 of the dual-pressure waste heat boiler, and the saturated water outlet of the low-pressure section 18 of the dual-pressure waste heat boiler is connected to the saturated water inlet of the coupled flash tank 5 through a pipeline; the water supply system includes a high-pressure feed water pump 6 and a low-pressure feed water pump 14, the outlet of the high-pressure feed water pump 6 is connected to the feed water inlet of the high-pressure section 1 of the dual-pressure waste heat boiler through a pipeline, the outlet of the low-pressure feed water pump 14 is connected to the feed water inlet of the low-pressure section 18 of the dual-pressure waste heat boiler through a pipeline, and the combined outlet after the saturated water outlet of the coupled flash tank 5 and the outlet of the steam seal heater 11 are combined is respectively connected to the inlet of the high-pressure feed water pump 6 and the inlet of the low-pressure feed water pump 14 through a pipeline.

[0041] Furthermore, a first bypass 12 for high-pressure steam to pass through is provided between the high-pressure section 1 of the dual-pressure waste heat boiler and the steam inlet of the coupled flash tank 5. The high-pressure steam can pass through the first bypass 12 without entering the high-pressure section 3 of the steam turbine. A switch valve is provided on the first bypass 12 to control the on and off of the first bypass 12.

[0042] Furthermore, a second bypass 13 for low-pressure steam to pass through is provided between the low-pressure reheat section 7 of the dual-pressure waste heat boiler and the inlet of the condenser 9. The low-pressure steam can pass through the second bypass 13 without entering the low-pressure section 8 of the turbine. A switch valve is provided on the second bypass 13 to control the on and off of the second bypass 13.

[0043] Furthermore, in this embodiment, the dual-pressure waste heat boiler uses a thermal deaerator 17 for deoxidation, and the thermal deaerator 17 is arranged at the confluent outlet after the saturated water outlet of the coupled flash tank 5 and the outlet of the steam seal heater 11 are confluent.

[0044] Furthermore, a liquid level gauge and a water replenishing device are provided on the coupled flash tank 5, so that the coupled flash tank 5 maintains a certain liquid level to prevent it from being sucked empty by the hot water pump.

[0045] Furthermore, it also includes a circulating water pump 20 and a cooling tower 19 , and the heat exchange pipeline in the condenser 9 is connected to the cooling tower 19 through the circulating water pump 20 .

[0046] Furthermore, the steam volume of the high-pressure section 1 of the dual-pressure waste heat boiler and the steam volume of the low-pressure section of the dual-pressure waste heat boiler are decoupled from the flue gas intake volume and the boiler exhaust temperature. The high-pressure feed water pump 6 is of industrial frequency or variable frequency, and the low-pressure feed water pump 14 is of industrial frequency or variable frequency. The feed water flow rate is adjusted by adjusting the valve. The control system controls the flow rates of the high-pressure feed water pump 6 and the low-pressure feed water pump 14 through the flue gas intake volume and the set boiler exhaust temperature, and thus controls the steam volume of the high-pressure section of the dual-pressure waste heat boiler and the steam volume of the low-pressure section of the dual-pressure waste heat boiler.

[0047] In this embodiment, the high-pressure section 1 of the double-pressure waste heat boiler includes a high-pressure economizer, a high-pressure evaporator, a high-pressure drum 2 and a high-pressure superheater, the low-pressure reheat section 7 of the double-pressure waste heat boiler includes a low-pressure reheater, and the low-pressure section 18 of the double-pressure waste heat boiler includes a low-pressure economizer, a low-pressure evaporator, a low-pressure drum 16 and a low-pressure superheater. During operation, high-temperature flue gas enters from the top air inlet of the double-pressure waste heat boiler, passes through the heating surfaces of the high-pressure section 1 of the double-pressure waste heat boiler, the low-pressure reheat section 7 of the double-pressure waste heat boiler, and the low-pressure section 18 of the double-pressure waste heat boiler in sequence, and is discharged from the bottom air outlet of the double-pressure waste heat boiler and enters the smoke exhaust system. The feed water from the high-pressure feed water pump 6 enters the high-pressure economizer to produce high-pressure saturated water, and the high-pressure saturated water enters the high-pressure evaporator, the high-pressure drum 2, and the high-pressure superheater in turn to produce high-pressure steam. The high-pressure steam enters the high-pressure section 3 of the steam turbine to do work and is then discharged into the coupled flash tank 5; the feed water from the low-pressure feed water pump 14 enters the low-pressure economizer to produce low-pressure saturated water I, a part of the low-pressure saturated water I enters the low-pressure evaporator, the low-pressure drum 16, and the low-pressure superheater in turn to produce low-pressure steam I, and the other part of the low-pressure saturated water I flows into the coupled flash tank 5; in the coupled flash tank 5, the inflowing low-pressure saturated water I and the low-pressure steam I are mixed with the low-pressure saturated water I from the steam drum 16. The exhaust steam from the high-pressure section 3 of the turbine is combined and mixed into low-pressure steam II and low-pressure saturated water II in the coupled flash tank 5; the low-pressure steam II enters the low-pressure reheat section 7 of the double-pressure waste heat boiler for reheating to generate low-pressure reheat steam, and the low-pressure reheat steam enters the low-pressure section 8 of the steam turbine to perform work, and the exhaust steam from the low-pressure section 8 of the steam turbine is condensed into condensate through the condenser 9; the condensate passes through the steam seal heater 11 and combines with the low-pressure saturated water II generated by the coupled flash tank 5, and then the combined water passes through the thermal deaerator 17, and the water feed system again transports the water to the high-pressure section 1 of the double-pressure waste heat boiler and the low-pressure section 18 of the double-pressure waste heat boiler.

[0048] In this embodiment, the saturated water entering the coupled flash tank 5 is low-pressure saturated water, and the operating pressure of the coupled flash tank 5 does not need to be consistent with the high-pressure saturated water, which is beneficial to reducing the cost of the coupled flash tank 5, improving the efficiency of the power generation system, and improving the thermal efficiency of the overall system.

[0049] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A dual-pressure flash waste heat power generation device, characterized in that: The invention comprises a double-pressure waste heat boiler, a steam turbine, a generator (4), a coupled flash tank (5), a feed water system, a condenser (9), a condensate pump (10) and a steam seal heater (11), wherein the steam turbine comprises a high-pressure section and a low-pressure section, and the double-pressure waste heat boiler comprises a high-pressure section and a low-pressure reheat section; the steam outlet of the high-pressure section (1) of the double-pressure waste heat boiler is connected to the inlet of the high-pressure section (3) of the steam turbine, the outlet of the high-pressure section (3) of the steam turbine is connected to the steam inlet of the coupled flash tank (5), the saturated water outlet of the double-pressure waste heat boiler is connected to the saturated water inlet of the coupled flash tank (5), and the saturated water outlet of the coupled flash tank (5) is connected to the inlet of the feed water system; the coupled flash The steam outlet of the steam drum (5) is connected to the steam inlet of the low-pressure reheat section (7) of the double-pressure waste heat boiler, the steam outlet of the low-pressure reheat section (7) of the double-pressure waste heat boiler is connected to the inlet of the low-pressure section (8) of the steam turbine, the outlet of the low-pressure section (8) of the steam turbine is connected to the inlet of the condenser (9), the outlet of the condenser (9) is connected to the inlet of the condensate pump (10), the inlet of the condensate pump (10) is connected to the inlet of the steam seal heater (11), the outlet of the steam seal heater (11) is connected to the inlet of the water supply system, and the outlet of the water supply system is connected to the water supply inlet of the high-pressure section (1) of the double-pressure waste heat boiler; the steam turbine is connected to the generator (4) to form a steam turbine power generation system.

2. A dual-pressure flash waste heat power generation device according to claim 1, characterized in that: A first bypass (12) for high-pressure steam to pass through is provided between the high-pressure section (1) of the double-pressure waste heat boiler and the steam inlet of the coupled flash tank (5), and a switch valve is provided on the first bypass (12).

3. A dual-pressure flash waste heat power generation device according to claim 1, characterized in that: A second bypass (13) for low-pressure steam to pass through is provided between the low-pressure reheat section (7) of the dual-pressure waste heat boiler and the inlet of the condenser (9), and a switch valve is provided on the second bypass (13).

4. A dual-pressure flash waste heat power generation device according to claim 1, characterized in that: Double-pressure waste heat boilers use chemical deoxidation, thermal deoxidation, vacuum deoxidation or condenser vacuuming to deoxidize.

5. A dual-pressure flash waste heat power generation device according to any one of claim 1, characterized in that: It also includes a circulating water pump (20) and a cooling tower (19), and the heat exchange pipeline in the condenser (9) is connected to the cooling tower (19) via the circulating water pump (20).

6. The dual-pressure flash waste heat power generation device according to claim 1, characterized in that: The saturated water outlet of the dual-pressure waste heat boiler is located on the high-pressure section; the water supply system comprises a high-pressure water supply pump (6), the outlet of the high-pressure water supply pump (6) is connected to the water supply inlet of the high-pressure section (1) of the dual-pressure waste heat boiler.

7. The dual-pressure flash waste heat power generation device according to claim 1, characterized in that: The double-pressure waste heat boiler also includes a low-pressure section, and the steam outlet of the low-pressure section (18) of the double-pressure waste heat boiler is connected to the steam inlet of the coupled flash tank (5); the saturated water outlet of the double-pressure waste heat boiler is located on the high-pressure section; the water supply system includes a high-pressure water supply pump (6) and a low-pressure water supply pump (14), the outlet of the high-pressure water supply pump (6) is connected to the water supply inlet of the high-pressure section (1) of the double-pressure waste heat boiler, and the outlet of the low-pressure water supply pump (14) is connected to the water supply inlet of the low-pressure section (18) of the double-pressure waste heat boiler.

8. The dual-pressure flash waste heat power generation device according to claim 1, characterized in that: The double-pressure waste heat boiler also includes a low-pressure section, and the steam outlet of the low-pressure section (18) of the double-pressure waste heat boiler is connected to the steam inlet of the coupled flash tank (5); the saturated water outlet of the double-pressure waste heat boiler is located on the low-pressure section; the water supply system includes a high-pressure water supply pump (6) and a low-pressure water supply pump (14), the outlet of the high-pressure water supply pump (6) is connected to the water supply inlet of the high-pressure section (1) of the double-pressure waste heat boiler, and the outlet of the low-pressure water supply pump (14) is connected to the water supply inlet of the low-pressure section (18) of the double-pressure waste heat boiler.

9. A dual-pressure flash waste heat power generation device according to claim 7 or 8, characterized in that: The steam volume of the low-pressure section (18) of the double-pressure waste heat boiler and the steam volume of the high-pressure section (1) of the double-pressure waste heat boiler are decoupled from the flue gas intake volume and the boiler exhaust gas temperature.

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